1. Field of the Invention:
The invention relates to products made by reacting a hindered phenol aldehyde with a nitrogen-containing compound, followed by reaction with a phosphorodithioic acid and to lubricant compositions containing same. More particularly, the product is made by reacting the aldehyde with a primary amine, followed by reaction thereof with a diorganophosphorodithioc acid.
2. Discussion of the Prior Art:
Many industrial organic media are used under circumstances which contribute to their breakdown during service. Such media include lubricants and greases, hydraulic fluids for brake and transmission systems, resins and plastics for coatings and structural articles. The severe operating conditions of modern engines, for example, including automotive and gas turbine engines, have often caused lubricating oils to deteriorate rapidly during use. This oxidation deterioration is accelerated by the use of higher engine operating temperatures than formerly used. Oxidative deterioration of the oil is usually accompanied by the formation of gummy deposits, sludge, acids, which may be strong enough to cause metal corrosion and other products of chemical breakdown. The products may seriously interfere with the lubrication operation. The increase in viscosity, for example, which results from the oxidation of lubricants, impairs the proper function of engine components and depreciates engine performance and useful life.
Organic media therefore may be blended with certain additives, termed "antioxidants" to protect against oxidation. Although many of the older known additives have been found to be adequate in stabilizing some modern mineral oil lubricants and synthetic lubricant blends, discovery of the new and more effective additives would be highly desirable for improved protection in current engines and extension of operating limits for future engines.
U.S. Pat. No. 3,644,172 discloses a product made by reacting a diorgano dithiophosphoric acid ester with a vinyl carboxylate. The product is useful as an antioxidant in lubricants.
U.S. Pat. No. 3,644,206 teaches a product useful as an antioxidant in an organic fluid. The product is made by reacting a diorganodithiophosphoric acid with a cyclic hindered aldehyde. The acid ester and the aldehyde react together in a 1:1 ratio.
It is one object of this invention to provide novel organic compositions which have improved oxidation stability and antiwear activity. It is a further object of this invention to provide novel compositions which afford protection against oxidation deterioration for organic media to which they have been added. Another object is to provide improved lubricating oil compositions capable of withstanding the oxidizing conditions of modern engines. These and other objects will become apparent from the following disclosure.